Engine air compressor [smog pump] bearings

[JLL13]

Hello to all the team. I was not much talkative since my registration, but spent time reading threads about that fantastic car. I own a [1992] 500E since 2003 (purchased for the birth of my son), and we have had wonderful travels with it.

The last trip was to Venise (Italy) with the family, that was in 2013, great memories. Since, the car sat in the garage: main reason is that we enjoy several cars (MB of course), and I was too much involved in my job and our home restoration project. End of 2016, I decided to start a restoration project on the 500E, from the trunk to the engine. Car remains very reliable and in good shape.

All was going fine until I reached the engine bay. A lot of stuff to work on, interesting to understand that engine, until I discovered and unplugged camshaft magnet. Why? Mmm, basically because the magnet was broken. So, purchased a new magnet, about to install it, ... but then came the first bad new of the restoration: high engine wiring harness totally cracked all the way. Ouaouh! I knew that was a weak part of the car, but discovering that wires was a great disappointment.

So, back to the dealer, purchase a harness, installed it, crossed fingers, and started the engine few weeks later: started, cranked, fired, and... ran from first try. Very impressed (although totally convinced these cars belong to the most reliable cars ever). Anyway, a strange noise coming from the front, right hand side (when driving the car, looking at the road) bothered me. Further tests later, and the issue did not fix by itself, so once again I decided to dig deeper. Yesterday I removed the serpentine belt (needs to be replaced also) and moved manually all the pulleys from all the accessories. No surprise at all when I turned the compressor's one (looking at the engine, hood opened, the one on the far left hand side, above the alternator's pulley): untight from its axle, and making pan noise, metal debris falling as dust, not a good signal at all.

So, the compressor's bearings are dead, the pulley is now blocked, and most of all: that part remains a mystery for most of us. Has anyone faced that issue? I insist that it is not the AC compressor (which is located at the right hand side when looking at the engine), but the air compressor. I wonder how one can remove it from the engine? I am pretty sure that once split out, I should be able to replace the bearings, or to install a new one.

So, that was a rather long story about our dream car. Hope I did not bother you too much.

Jean-Louis

 

[nocfn]

Re: Engine air compressor bearings

So its the air pump that is broken. There are links on here about replacing it, or getting a delete mechanism. It only runs for a few moments, but constantly spins so I can imagine the noise.... Sear for Air pump, see what you get.


EDIT http://www.500eboard.com/forums/showthread.php?t=9587&p=125214&viewfull=1#post125214

 

[gsxr]

Another thread on the bearing replacement:

http://www.500eboard.com/forums/showthread.php?t=11733

 

[samiam44]

If you search the web, a similar era car with more writeups is a 928. I remember one where the guy replaces *all* the internal bearings plus the pulley.

 

[luckymike]

Re: Engine air compressor bearings

Jean-Louis,

I am dealing with this problem right now.

The bearing is pretty easy to replace. The problem is finding the bearing. In the United States, it appears to be a proprietary bearing and no one will carry it or sell it to the public. I did a lot of research.

You can try this bearing number in Europe: PC30460018CS.

My ultimate solution was to find a good air pump at a dismantler.

It is easy to remove the pump. Two bolts hold it in place and then it lifts out the top of the engine on my E420. The hard part was removing the clamp that holds the rubber air line in place.

 

[gsxr]

Isn't this bearing still available?

https://bearingsdirect.com/automoti...-ball-bearing-32x52x18-20-l32-52-2rsoh03.html

PC30460018CS appears to be a different size...

 

[luckymike]

Isn't this bearing still available?

https://bearingsdirect.com/automoti...-ball-bearing-32x52x18-20-l32-52-2rsoh03.html

PC30460018CS appears to be a different size...

It does look like that bearing is available. But it's a 32 X 52 X 18. For my '95 E420, I need 30 x 46 x 18.

 

[gsxr]

It does look like that bearing is available. But it's a 32 X 52 X 18. For my '95 E420, I need 30 x 46 x 18.

Are you 100% certain? I investigated this a number of years ago and the 32 X 52 X 18 bearing is what was coming up as the correct pulley bearing.

EDIT: One size is for 8-rib pulleys (1992) and the other for 6-rib (93-95). I think the following is correct:

6 rib = 30x46x18
8 rib = 32x52x18​

 

[luckymike]

Are you 100% certain? I investigated this a number of years ago and the 32 X 52 X 18 bearing is what was coming up as the correct pulley bearing. Maybe one is for 8-rib pulleys (1992) and the other for 6-rib (93-95). Now I'll have to look at them again...

I'm 100% certain. And my pulley is 6-rib, 92mm in diameter.

 

[M104]

PC30460018CS is the right bearing for 6-grove pulley. I replaced it last year. In my country it's easily accessible, costs approximately 30$.

 

[Efraim]

I’m intensively following this talk since the air pump rebuilding is ahead of me. On the last week the pump stuck as result pulley with red heat and some smoke. The engine was running only some seconds when reversing from my garage but still it had time to turn red. I can't imagine what would happend if the engine run longer. This happened almost without pre warning, only once a week before the suction noise was slightly bigger, but the noise vanished until the incident. Now the pump is unplugged and engine and belt is running ok.

I suggest to take seriously all abnormal noises of that pump.

 

[nocfn]

Wish i could unplug it like the W126 here in the states. I actually shed almost 15 lbs and sold it for $100 to an owner in the socialist republic of California where it is required to run for 11 seconds at cold startup.

 

[JLL13]

Many many thanks for your replies, guys (and girls may be?).
So far, my main concern is to split the air pump apart from the engine.
Then, I will investigate further about the bearings or for a part replacement.

I will not have time to look after this issue before nextasaturday, so do not be upset if I do not answer immediately.
My diag as of today is: the pulley (of the air pump) does not turn around its axle. Not more.

Will read carefully the threads mentionned above and unerstand how to unbolt the pump.
Great site, by the way, great forum, very skilled people there.
Hope to contribute.

Jean-Louis

 

[Hakie]

I ordered 2 of the bearing for both my 400E and E500 from this website. They send to a list of countries to be selected in a list. They also send to USA.

http://www.dswaelzlager.de/Kompressorlager-PC30460018CS-PFI-30x46x16-18-

I payed €47,77 including sending. (€16,90 netto/each).
I will report here when i have them.

 

[doolar]

I always run my car with it disconnected, my pump makes one hell of a racket when engaged. I guess you can't in the US since it triggers the CEL. It's a connector in front of the expansion tank. But I assume you all know that. One day I'll get the delete bracket and just uninstall it altogether.

 

[gsxr]

I always run my car with it disconnected, my pump makes one hell of a racket when engaged. I guess you can't in the US since it triggers the CEL. It's a connector in front of the expansion tank. But I assume you all know that. One day I'll get the delete bracket and just uninstall it altogether.

This is correct - disconnecting the pump will trigger a CEL on USA models. If the pump is very noise when operating, it is probably on its last legs and nearing death. Good ones are almost silent running.

However, when the electrical connector is unplugged, all that does is trigger an annoying light on the dash... and the bulb can be removed... not that I'm recommending this for a street-driven car.

 

[JLL13]

So, huge progress today, I got the pump disassembled away from the engine.
Quite a difficult job I would say, mainly because I challenged myself getting it out with removing less other parts as possible.
The biggest problem was to access the wire plug that is under the passenger's front headlight!
When I will put the pump back, I will keep the wire connector away from the headlight inner cover (so, in case there is a need of, the next service will be much eased).

Anyway, now the pump is on the workbench, and I can forecast another huge difficulty: the front nut is strongly, strongly, strongly bolt on the shaft.
I tried several ways to unbolt... nothing seems to be effective at first try.
I opened up the pump from its behind cover, and have access to the whole mecanism, but even that way, no easy method to get the nut untight.

To be continued... with pictures I shot.

Jean-Louis

 

[luckymike]

Did you already try placing an allen socket in the shaft as a counterhold? I was surprised at how well this worked on both of my smog pumps. The nuts both came loose quite easily.

 

[samiam44]

Impact wrench to remove.

 

[JLL13]

Did you already try placing an allen socket in the shaft as a counterhold? I was surprised at how well this worked on both of my smog pumps. The nuts both came loose quite easily.

Yes, done already.
Put an allen key in the center, try to force... no change.
I need to purchase a special 22mm opened pipe wrench.
Combined with an allen key, that could be more powerfull.

But I think a mechanic could do that is a second, I will try to find one in the neighborhood.

Jean-Louis

 

[luckymike]

Yes, done already.
Put an allen key in the center, try to force... no change.
I need to purchase a special 22mm opened pipe wrench.
Combined with an allen key, that could be more powerfull.

But I think a mechanic could do that is a second, I will try to find one in the neighborhood.

Jean-Louis

Remember, the trick is to 'snap' the nut loose. Don't apply slow pressure. You want a quick, deliberate shock.

 

[samm]

Im hoping to receive the new bearing this coming week. After reading this thread Im going to try and get that nut off with a long bar while the pump is on the car. If not I'll have to purchase a good old snap on impact wrench again...

 

[samm]

ok i just got the nut off. its not 22m i think its 21mm but I used some SAE wrench and Im not sure what the size was. I put a long steel pipe over the wrench and held the center allen with a long ratchet. quick pull and it came loose.

 

[luckymike]

ok i just got the nut off. its not 22m i think its 21mm but I used some SAE wrench and Im not sure what the size was. I put a long steel pipe over the wrench and held the center allen with a long ratchet. quick pull and it came loose.

There you go.

 

[Hakie]

I ordered 2 of the bearing for both my 400E and E500 from this website. They send to a list of countries to be selected in a list. They also send to USA.

http://www.dswaelzlager.de/Kompressorlager-PC30460018CS-PFI-30x46x16-18-

I payed €47,77 including sending. (€16,90 netto/each).
I will report here when i have them.

Got the bearings today.

 

[samm]

It does look like that bearing is available. But it's a 32 X 52 X 18. For my '95 E420, I need 30 x 46 x 18.

correct. My 95 420 has this 46 30 18 bearing

 

[gsxr]

Found a USA vendor that appears to have the correct size 30x46x18/20 bearing for the 6-rib pulley bearings, for 1993-1995 USA model year M119 engines:

https://bearingsdirect.com/automoti...ressor-ball-bearing-30x46xod-w16-id-w-18.html

Don't have any confirmation yet but it looks promising.

 

[samm]

Found a USA vendor that appears to have the correct size 30x46x18/20 bearing for the 6-rib pulley bearings, for 1993-1995 USA model year M119 engines:

https://bearingsdirect.com/automoti...ressor-ball-bearing-30x46xod-w16-id-w-18.html

Don't have any confirmation yet but it looks promising.

hey..yes thats where I bought mine from a few days ago... dont know how good PFI is though

 

[gsxr]

hey..yes thats where I bought mine from a few days ago... dont know how good PFI is though

Please post some photos when you receive the bearings! I assume they will be made in China, but it's not like we have much choice. If you're picky you could try to open up the dust seal and add some grease if necessary - or just install and see how it works.

 

[samiam44]

I would just install it- cannot get the original brg as it is specifically made for Denso and not an off the shelf size.


I wouldn't add grease to it- some greases are not compatible and would lead to early failure. I've done this brg replacement several times. Not difficult. Just be careful to support the housing properly when pressing as the pulley is soft metal.

Michael

 

[samm]

Yes I will do that, nowadays it so much easier to post pics on forums. Years ago I used to have difficulty with the sizes!

 

[samm]

I will post pictures, not open the seal!

 

[samm]

 

[samm]

By the way my bearing was a little noisy but it doesnt look damaged at all. I will open up the seal on that one

 

[samm]

By the way my bearing was a little noisy but it doesnt look damaged at all. I will open up the seal on that one

OK here is the new bearing. A bit disappointed it's made in China and I'm not sure who made it (c&s)
I am not installing it until I check if I can find a better one.

 

[samiam44]

I wish you luck, but I remember asking the bearing manufacture about the bearing. It is a vendor controlled part- so the only source for the OE bearing is by buying a clutch assembly from Benz. The bearings are not highly loaded and the chinese made bearings seem to be lasting.

 

[samm]

I wish you luck, but I remember asking the bearing manufacture about the bearing. It is a vendor controlled part- so the only source for the OE bearing is by buying a clutch assembly from Benz. The bearings are not highly loaded and the chinese made bearings seem to be lasting.

Hey Sam
Thank you for your valuable input.
Do you know if the PFI bearings are made in China too? The thing that bugs me is that my bearing came in a plain brown box. Now that just doesn't Inspire confidence at all.
Maybe I should open the seal and put in some high temp grease in there in case?
I'm disappointed that I may be forced to put this bearing into the pump. I will also look into having.the delete kit sent to me from England. The pulley and the bracket.

 

[JLL13]

Hello all, happy to report a progress on the air pump fixing:


Yesterday, I spent few dozens of minutes checking the pump, and trying to remove that famous center bolt.
Prior to that, I purchased a 22mm wrench. A specific wrench enabling an allen key to go in and block the axis while the wrench unscrews the bolt:


I must say that specific wrench was not necessary, a standard 22 wrench could have done the job.
Anyway, the most important is that the bolt is now out, and the bearings can be replaced.
I first had to dismantle the pump, its back, and get access to the rotor itself and get it blocked inside the pump shell (sorry for the picture quality):


Then, once the inner rotor was blocked, I installed a lever on the outside shell:


That preperation made the job much more easier than all previous attemps. In a second, the bolt was loosened with a moderate pressure on the wrench:


So, here we are:


After taking off the clips, I discovered a true carnage inside the pump. I still wonder how it did not destroy itself:



I am now facing the next step, and most probably I will have to replace further parts than the bearings. Here are the parts numbers. By the way, I have half a bearing (the inner side), the second half (outer side) being soldered to the wheel.


First, many thanks for all the valuable inputs you gave.
Second, what would you do in such a situation?

Jean-Louis

 

[luckymike]

I used a punch to drive the outer race out of the pulley. No problem. It looks like your inner race is stuck on the shaft. I would probably use a Dremel to cut a couple grooves in it. Then heat it up to expand it and use a punch to tap it off.

 

[samiam44]

Honestly, I think that ones is done- go find a good used one. You can re-bearing a used one and clean it up.

If you can get the brg inner race off and there isn't scoring damage- I can try and match the coil. Just give me the ID/OD/ Depth.


You can get a used one- they are somewhat common ~ $125 shipped generally. Consider replacing the check valve too.

 

[JLL13]

Thanks guys.
From pic #9 and 10, you can notice the pulley, the inner bearings race, all the bearings (24), and soldered to the pulley the outer bearings race (that is in the inner side of the pulley of course). Then, the magnet.
From my diag (and I am not expert, you can challenge me from the pictures), the magnet is totally, totally, absolutely and 100% sure ooo.
The pulley seems good enough, but the outer bearings is in there. I will try the method you describe luckymike.
Then, the pump itself seems in good condition as well, just a little bit of cleaning and put all parts back together, almost certain I can do that.

I started looking at the whole pump as you suggest samiam44, but my point is that they do not look better than mine (apart from the damaged bearings and magnet of course). So purchasing a used one, plus replacing the bearings would remain a good option?

Jean-Louis

 

[samiam44]

I've always wondered, if the pulley from a dense compressor might match. Can't get an exact diameter, but 3.5-3.75 inch diameter. Like I said before, you can match a magnet. I think the air pump is similar and used on other cars.

 

[samiam44]

The magnet we throw out at work is 3.75 od, 2.5 id, 1.25 thick.

What do you need?

 

[gsxr]

Here's a tip in case you buy a used pump: Bench-test the pump first. To do this, use a drill with an adapter that allows a socket to be connected, and spin the large hex nut to drive the pump with the drill. If it sounds like it's full of marbles, you at least avoided installing a bad pump. Wouldn't hurt to test the coil as well, apply 12v and you should see the clutch engage visibly and with an audible click. Finally - most of the rubber hoses tended to be fossilized after 25 years near the exhaust manifold. This is a good time to replace the rubber hoses, there are 3 of them IIRC plus a few plastic connecting pieces.

 

[samiam44]

Jean-Louis,

I guess it depends where you are at- for me, I know these are plentiful in the junkyards. There are plenty of them and I've got a few spares.

Anyway, I just don't see air pumps as valueable to save. I would get a clean used one and put a new bearing in the idler- clean and grease the other ones- if you are going all-out. Rebuilt ones run ~$300 and require a rebuildable core.


M

 

[gsxr]

Note that Jean-Louis has a 1992 with 8-rib pulley... so he'd ideally need a replacement pump with the same part number / pulley. These were 1992-only units for the 400E/500E, I'm not sure if they were used on other models and if so, what cars would be donors.

 

[samiam44]

034s. I've passed on many 8 ribers. I think there is on close to me.. didn't check it.

 

[MikeinTampa]

I snapped a photo of mine yesterday. It's a bit noisy only when engaged. I don't think this is the original pump either. Correct?

 

[gsxr]

I snapped a photo of mine yesterday. It's a bit noisy only when engaged. I don't think this is the original pump either. Correct?

That is a 1992 pump... but IIRC, your car had an engine swap with a 1993 engine. (??) So it may be the pump original to the car, not the engine. The 6-rib belt setup has a different pulley diameter for the air pump, and a different belt length between 8 rib and 6 rib. Ideally, you'd replace it with a 6-rib pump, but you'd also need to make sure your existing belt is the correct/stock length.

 

[JLL13]

Hi gents, and again, many thanks for the interest, help, and patience.
I read all your posts.

I will not be able put the hands on the pump before next week, we celebrate the birthday of my son these coming saturday and sunday, with all the family coming to visit us.
So... I will have to wait a little bit to show progress on that issue.

Jean-Louis